I ended up getting past with one man with a pistol in DC, having to shoot only the 2 right-most men.
After that I threw a nade in the middle of about 10 sleeping men (couldn't resist) on top of the hill and found that they get infinite off-map reinforcements until you sound the alarm anyway.
I noticed that patrols go through every bush. You can't hide bodies anywhere. Those soldiers deserve a medal for dedication to duty. The next Hitman game should have guards that check under every trash can lid every 5 minutes.